X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=8a66812a79c1eda84909dc20d09ead945a1c89de;hp=328b13e66303ea2dc24361f0a247143ae9fc028b;hb=9edc7d6958fd616daecb0ab9ae2aa92042b3d34a;hpb=d786822b92c26d758ea2f2f21368a4cfcce43ca8 diff --git a/src/tt.cpp b/src/tt.cpp index 328b13e6..8a66812a 100644 --- a/src/tt.cpp +++ b/src/tt.cpp @@ -1,247 +1,144 @@ /* - Glaurung, a UCI chess playing engine. - Copyright (C) 2004-2008 Tord Romstad + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad - Glaurung is free software: you can redistribute it and/or modify + Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - - Glaurung is distributed in the hope that it will be useful, + + Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. - + You should have received a copy of the GNU General Public License along with this program. If not, see . */ +#include +#include -//// -//// Includes -//// - -#include -#include - +#include "bitboard.h" #include "tt.h" +TranspositionTable TT; // Our global transposition table -//// -//// Functions -//// +TranspositionTable::TranspositionTable() { -/// Constructor - -TranspositionTable::TranspositionTable(unsigned mbSize) { - - size = 0; - generation = 0; - writes = 0; - entries = 0; - set_size(mbSize); + size = generation = 0; + entries = NULL; } - -/// Destructor - TranspositionTable::~TranspositionTable() { delete [] entries; } -/// TranspositionTable::set_size sets the size of the transposition table, -/// measured in megabytes. +/// TranspositionTable::set_size() sets the size of the transposition table, +/// measured in megabytes. Transposition table consists of a power of 2 number of +/// TTCluster and each cluster consists of ClusterSize number of TTEntries. Each +/// non-empty entry contains information of exactly one position. + +void TranspositionTable::set_size(size_t mbSize) { -void TranspositionTable::set_size(unsigned mbSize) { + size_t newSize = 1ULL << msb((mbSize << 20) / sizeof(TTCluster)); - assert(mbSize >= 4 && mbSize <= 1024); + if (newSize == size) + return; - unsigned newSize = 1024; + size = newSize; + delete [] entries; + entries = new (std::nothrow) TTCluster[size]; - // We store a cluster of 4 TTEntry for each position and newSize is - // the maximum number of storable positions - for ( ; newSize * 4 * (sizeof(TTEntry)) <= (mbSize << 20); newSize *= 2); - newSize /= 2; - if (newSize != size) + if (!entries) { - size = newSize; - delete [] entries; - entries = new TTEntry[size * 4]; - if (!entries) - { std::cerr << "Failed to allocate " << mbSize - << " MB for transposition table." - << std::endl; + << "MB for transposition table." << std::endl; exit(EXIT_FAILURE); - } - clear(); } + + clear(); // Operator new is not guaranteed to initialize memory to zero } -/// TranspositionTable::clear overwrites the entire transposition table -/// with zeroes. It is called whenever the table is resized, or when the +/// TranspositionTable::clear() overwrites the entire transposition table +/// with zeroes. It is called whenever the table is resized, or when the /// user asks the program to clear the table (from the UCI interface). -/// Perhaps we should also clear it when the "ucinewgame" command is recieved? void TranspositionTable::clear() { - memset(entries, 0, size * 4 * sizeof(TTEntry)); + memset(entries, 0, size * sizeof(TTCluster)); } -/// TranspositionTable::store writes a new entry containing a position, -/// a value, a value type, a search depth, and a best move to the -/// transposition table. The transposition table is organized in clusters -/// of four TTEntry objects, and when a new entry is written, it replaces -/// the least valuable of the four entries in a cluster. A TTEntry t1 is -/// considered to be more valuable than a TTEntry t2 if t1 is from the -/// current search and t2 is from a previous search, or if the depth of t1 -/// is bigger than the depth of t2. +/// TranspositionTable::store() writes a new entry containing position key and +/// valuable information of current position. The lowest order bits of position +/// key are used to decide on which cluster the position will be placed. +/// When a new entry is written and there are no empty entries available in cluster, +/// it replaces the least valuable of entries. A TTEntry t1 is considered to be +/// more valuable than a TTEntry t2 if t1 is from the current search and t2 is from +/// a previous search, or if the depth of t1 is bigger than the depth of t2. -void TranspositionTable::store(const Position &pos, Value v, Depth d, - Move m, ValueType type) { - TTEntry *tte, *replace; - - tte = replace = entries + int(pos.get_key() & (size - 1)) * 4; - for (int i = 0; i < 4; i++) - { - if (!(tte+i)->key()) // still empty - { - *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation); - writes++; - return; - } - if ((tte+i)->key() == pos.get_key()) // overwrite old - { - if (m == MOVE_NONE) - m = (tte+i)->move(); - - *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation); - return; - } - if ( i == 0 // already is (replace == tte+i), common case - || replace->generation() < (tte+i)->generation()) - continue; - - if ( replace->generation() > (tte+i)->generation() - || (tte+i)->depth() < replace->depth()) - replace = tte+i; - } - *replace = TTEntry(pos.get_key(), v, type, d, m, generation); - writes++; -} +void TranspositionTable::store(const Key posKey, Value v, Bound b, Depth d, Move m) { + int c1, c2, c3; + TTEntry *tte, *replace; + uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key inside the cluster -/// TranspositionTable::retrieve looks up the current position in the -/// transposition table, and extracts the value, value type, depth and -/// best move if the position is found. The return value is true if -/// the position is found, and false if it isn't. + tte = replace = first_entry(posKey); -bool TranspositionTable::retrieve(const Position &pos, Value *value, - Depth *d, Move *move, - ValueType *type) const { - TTEntry *tte; - bool found = false; + for (int i = 0; i < ClusterSize; i++, tte++) + { + if (!tte->key()) + tte->save(posKey32, v, b, d, m, generation); - tte = entries + int(pos.get_key() & (size - 1)) * 4; - for (int i = 0; i < 4 && !found ; i++) - if ((tte+i)->key() == pos.get_key()) + if (tte->key() == posKey32) { - tte = tte + i; - found = true; - } - if (!found) { - *move = MOVE_NONE; - return false; - } - *value = tte->value(); - *type = tte->type(); - *d = tte->depth(); - *move = tte->move(); - return true; -} - - -/// TranspositionTable::new_search() is called at the beginning of every new -/// search. It increments the "generation" variable, which is used to -/// distinguish transposition table entries from previous searches from -/// entries from the current search. - -void TranspositionTable::new_search() { - - generation++; - writes = 0; -} + // Preserve any existing ttMove + if (m == MOVE_NONE) + m = tte->move(); + tte->update(v, b, d, m, generation); + return; + } -/// TranspositionTable::insert_pv() is called at the end of a search -/// iteration, and inserts the PV back into the PV. This makes sure the -/// old PV moves are searched first, even if the old TT entries have been -/// overwritten. - -void TranspositionTable::insert_pv(const Position &pos, Move pv[]) { - - UndoInfo u; - Position p(pos); + // Implement replace strategy + c1 = (replace->generation() == generation ? 2 : 0); + c2 = (tte->generation() == generation || tte->type() == BOUND_EXACT ? -2 : 0); + c3 = (tte->depth() < replace->depth() ? 1 : 0); - for (int i = 0; pv[i] != MOVE_NONE; i++) - { - store(p, VALUE_NONE, Depth(0), pv[i], VALUE_TYPE_NONE); - p.do_move(pv[i], u); + if (c1 + c2 + c3 > 0) + replace = tte; } + replace->save(posKey32, v, b, d, m, generation); } -/// TranspositionTable::full() returns the permill of all transposition table -/// entries which have received at least one write during the current search. -/// It is used to display the "info hashfull ..." information in UCI. - -int TranspositionTable::full() { +/// TranspositionTable::probe() looks up the current position in the +/// transposition table. Returns a pointer to the TTEntry or NULL if +/// position is not found. - double N = double(size) * 4.0; - return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N)))); -} +TTEntry* TranspositionTable::probe(const Key posKey) const { + uint32_t posKey32 = posKey >> 32; + TTEntry* tte = first_entry(posKey); -/// Constructors + for (int i = 0; i < ClusterSize; i++, tte++) + if (tte->key() == posKey32) + return tte; -TTEntry::TTEntry() { + return NULL; } -TTEntry::TTEntry(Key k, Value v, ValueType t, Depth d, Move m, - int generation) { - key_ = k; - data = (m & 0x7FFFF) | (t << 20) | (generation << 23); - value_ = v; - depth_ = int16_t(d); -} +/// TranspositionTable::new_search() is called at the beginning of every new +/// search. It increments the "generation" variable, which is used to +/// distinguish transposition table entries from previous searches from +/// entries from the current search. -/// Functions for extracting data from TTEntry objects. - -inline Key TTEntry::key() const { - return key_; -} - -inline Depth TTEntry::depth() const { - return Depth(depth_); -} - -inline Move TTEntry::move() const { - return Move(data & 0x7FFFF); -} - -inline Value TTEntry::value() const { - return Value(value_); -} - -inline ValueType TTEntry::type() const { - return ValueType((data >> 20) & 3); -} - -inline int TTEntry::generation() const { - return (data >> 23); +void TranspositionTable::new_search() { + generation++; }